Reversible screw-propeller.



A. DISKOLS. REVERSIBLE SCREW PROPELLER.

APPLICATION FILED IuNE5, I9I5.

l,18l,458. Patented May 2,1916.

fnvenior.

rzafol .Dowz'ol fskols.

ANATOL DAVID IsKoLs, or SGHENECTDY, NEW Yoan.

nEvEBsIBLE SCREW-PROPELLER.-

inertes.

Speciiication of Letters Patent. Patented 1916.

Application filed .Tun`e 5, 19.15, Serial No. 32,446.

To allwhom t may concern Be it known that I, ANAToL DAVID IsKoLs, a resident of the city of Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in nReversible Screw-Propellers, of which the following is a specification.

My invention relates to that type of screw propeller for marine propulsion in which the blades are so mounted that they can be turned on their axes for theipurpose offreversing the direction of movement of the boat or vessel propelled thereby without reversing thedriving engine.

Reversible screw propellers as now constructed have the blades pivotally secured at Vtheir bases only, with the result that the i reaction of the water, (which can be considered as a single resulting force acting at the center of pressure of the blade with a lever arm equal to the distance of said center from the base) creates a bending moment which imposes a considerable stress on the pivot of each blade. For large propellers and large engine capacities these stresses rise to such magnitude as to prevent the use of such constructions as have heretofore been available. To meet the problem of reversing vessels providedwith' cost of the installation..

My present invention has for `its object to overcome the objections above noted and to provide a reversible propellerl of improved "construction which is capablebf claims appended thereto. l,

In the accompanying drawing which is' illustrative of my invention,lFigure l-is an axial section of a reversible propeller Fig. 2 is a similar view'of a modification showing an electric motor located within the hub of th e propeller for turning the blades thereon, and Fig. `3 is a diagrammatic illustration of a means for indicating the angular position of the blades. i.

. l indicates the hub of the propeller which 1s made hollow to receive certain operating parts-as. will lappear later. It is mounted on the tail or propeller shaft2 in any suitable way. As shown the rear end of the shaft is made conical and the hub is snugly fitted thereto and heldin place by a feather 3 and nut 4, the latter being accessible when the cover or cap 5 is removed. The hub is provided with as many stands'or pedestals 6 as there are blades. As shown the stands are formed integral with the hub as ordinarily this\is the best construction, but

under certain circumstances they may be' made separable. Thev arrangementof th'esc stands 1s lmportant. Each extends outwardly to and preferably somewhat beyond the center of pressureof the blade supported thereby. By the center of pressure is meant that point or region of the blade where the hydraulic pressure above and below it (considering a blade to be standing vert-ical) will be substantially balanced; The advantage of this over fastening the blade at its inner end or base resides in the fact that in the latter case the pivot is subf jected not only to pressure and resulting friction but also to bending with the resulting tendency to cramp and thus to destroy or to greatly interfere with the reversibility vof the blade. In my improved construction the pivot of each blade when in action, is balanced, being located right at the point ofv application of the resulting force and hence is lsubject only to pressure and'resulting friction, which is naturally unavoidable, but which can easily be taken care of withllltdinterfering with the reversiblity of the Theoretically tlfe bearing for the blade should be a point and register with that of thecent'er of pressure,'but this is impossible in practice because the bearing surfaces must have substantial areas. Each 'stand is bored centrally to receive the spindle or pivot 7 which is supported in suitable beary, ings, and ismade slightly conical to give it the necessary strength at the point ofattachment to the hub. IIhe lower end of each stand is turned true and m'ay ifidesired form a guide for the lower end of the annular hub formed in the blade. It is preferable to make this a Vgood it to excludev water as completely as possible. The space 8 around the stand may be filled with a heavy grease for the samepurpose.

The propeller blades 9 are of suitable shape and have the necesseary areal and pitch to drive the vessel at the required speed, it being assumed of course that the engine has the proper4 capacity. Each blade has a hub 10 containing a conical bore that closely surrounds the stand at the end adjacent the hub. To the outer end of the hub is se- .cured the pivot 7 by any suitable means,

as for example by a screw thread. By turning the pivot on its bearings the pitch of the blade can be increased or decreased at will and also reversed.

In order to adjust the position of the blades the following means are provided. On the inner endof each pivot is rigidly mounted a crank 1.1 Whose pin is connected by a'link 12 lwith a pin or trunnion on the sliding block 13. This block is mounted in guides 15 formed on the hub 1 and is reciprocated by the rod 16, the latter extending through the tail shaft 2 into the engine room or other'- convenient point in the vessel, where it is attached to suitable means for moving it longitudinally but which permit it to turn freely with the shaft. Access to this block may be had by removing the cover 5. In order to prevent water from working into the hub vthrough the various A joints the space not occupied by the moving parts is filled with suitable grease which also acts as a lubricant. As the block moves to and fro it displaces the grease from the chamber on one side of it to that on the other through the passage`17, of which al number may be provided. As the block is moved forward or aft by the rod 16, its

. counter shaft .22. a gear that meshes with a p1n1onv23 on the armatureofthe electric motor 24. ABy means movementis communicated by the links 12 to the cranks on,the blade spindles or pivots 7 and the latter are turned by an amount and in the direction` determined by the block. This movement may be enough to reverse the blades or merely to change the angle of pitch.

- Fig. 2 illustrates a construction intended for'flarge engines and vessels. In this case the sliding block 13 which moves the blades .end of the "tail shaft 2. The forward vend of the sleeve is provided with.v a gear 20 that meshes with a pinion 21 mounted on a On the counter shaft is the thrust or tendency of the blades to turn on their axes when' in operation is insuflicient to move the sliding block.l The motor is mounted on a bracket 25 that lis preferably attached to and moves with the' sliding block 1-3. The leads for the motor extend through the hollow tail shaft to slip rings 14 mounted on .said shaft but insulated therefrom. Riding on these rings are brushes 26 that are connected to a source of current through. conductors 27, and a reversing switch 28, the blades of which are shown in dotted lines in one of its positions. As the motor armature revolves in one direction or the other, as determined by the switch, it revolves the sleeve or nut 18 on the screw 19 thereby moving the sliding block and with it the blades, as described in connection with Fig. 1. The chamber within the hub 1 is filled with suitable grease to keep out the water and also to lubricate the parts. The movements of the block cause the grease to pass through the passages 17 from one side thereof to the other. Mounting the motor on the block results in a mechanical simplification of the'apparatus as a whole, and affords anv arrangement which is extremely simple' to construct and keep in order. As it is customary tooverhaul lvessels at certain intervals, the blades and their adjusting means can be looked after at the same time and the grease renewed.

In order to indicate Ithe position of the propeller blades, an arrangement such as is -shown diagrammatically in Fig. 3 may be employed. Mounted on the sliding block 1h10 13 and insulated therefrom is a circuit closer 30 which at the rear position of the block engages two stationary contacts 31 carried by some part of the hub. Theseare connected by wires 32, leading through the tail shaft to an electrically actuated indicator 33 of any suitable construction located at any convenient or desirable place within the vessel.

reached the forward end of`its travel. If it be desired to indicate intermediate ositions of the sliding block and hence o the blades, other and similar contacts maybe provided andoset at intermediate points.

In accordance with the provisions. of the A similar'set Vof contacts 35 is arranged to indicate when the block has'120 patent statutes, I have described the principle-of operation of my invention, together Vwith the apparatus which I now consider to represent the best embodiment thereof.; but I desire to haveit understood .that the .iso

apparatus shown is only illustrative, and that the invention can be carried out by other means within the scope of the Happended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

l. In a reversible screw propeller, the combination of a hub having stands projecting outwardly therefrom to substantially the center of hydraulic pressure region of the blades,` blades4 mounted thereon and arranged to be angularly adjusted, each blade being supported on a stand at substantially its center of hydraulic pressure region, spindles `that are supported by the stands, each of which is attached to a blade, and means located Within the hub for turning the spindles and blades.

2. In a reversible screw propeller, the combination of a hub having stands thereon, each of which extends outwardly therefrom, blades pivotally mounted on the stands, bearings for the blades, the bearings and the outer ends of the stands being located at "substantially the center of pressure Iregion of the blades, and-means located within the hub for turning the blades angularly about their axes.

3. In a reversible n screw propeller, the combination of a hub having stands projecting outwardly therefrom to substantially the center of pressure region of the blades, blades having hubs which receive the standsand are. supported thereby, pivots that are secured 'to' the blades and pass through the stands into the hub, actuators.

attached to the pivots, and means common to the actuators for moving them to change the positions of the blades.

4. In a reversible screw propeller, the combination of ahub having stands projecting outwardly therefrom to substantially the center of hydraulic pressure region of the blades, blades, pivots for4 the blades mountedrin the stands and supported there,- by at substantially the .center of the 'hydraulic pressure regions of the blades, a

sliding block within the hub, cranks attached to the pivots and connected to the block, and

-means for moving the block to and fro.

5. In a reversible screw' propeller, the

blades, blades mounted. thereon, pivots for the blades that extend through the stands into the'r hub, a sliding block, means for transmitting movements of the block to the pivots to turnthe blades, and an electric motor for moving the block forward and backward. I

6. In. a reversible screw propeller, the combination of a hollow hub having stands projecting outwardly therefrom to substantially the center of pressure region of the blades, blades mounted thereon, pivots for the blades that extend into the hub, a sliding block located in the hub, motion transmitting connections between the pivots and block', a nut and screw for moving the block, and an electric motor for imparting relative movements to the nut and screw to move the blades.

7. Inv a reversible propeller,.the combination'of ahollow hub having stands projecting therefrom to substantially the center of pressure region ofthe blades, blades mount-y ed thereon, pivots for the blades that extend through the stands into the hub, asliding block which has fore and aft movement in --motor carried by the block for causing rela.-

tive rotary motion of the nut and screw.

.8. Inl a reversible screw propeller, the combination of a hub having stands projecting outwardly therefrom to' substantially the center of pressure region of the blades, blades mounted thereon, means extending through the stands for moving the blades angularly, an actuator for the means located within the hub, an electric indicator adapted to be located aboard the vessel, and means within the hub for controlling the circuit of the indicator `to cause the indicator to show the position of the actuator. i

In witness whereof, I have hereunto set my hand this 4th dayof June, 1915.

ANAToL nAvin isKoLs. 

